Tomcat 5.0 and 5.5

I am quite new to the SCWCD exam although I do use Servlets and JSP at work. I have recently started to study for it.

I downloaded Tomcat 5.5 as I believe this is the lasted version. To my understanding Tomcat 5.5 is for J2SE 5.0 and Tomcat 5.0 is for J2SE 1.4.

I have got both J2SE 5.0 and J2SE 1.4.2 installed but I am having trouble running Tomcat 5.5. It works but applications I have deployed don't seem to work. With 5.0 they work.

Has anyone else had any problems with 5.5 or am I doing something wrong. I know that Tomcat 5.5 is working with J2SE 5.0 and Tomcat 5.0 is working with J2SE 1.4.2 on my machine. So it's not that they are running though the wrong JVM versions.

Anyone have any comments on Tomcat 5.5 as oppose to Tomcat 5.0? Which one is the one I should use? Are there any differences in the Tomcat code from 5.0 to 5.5 other then compatibility issues with J2SE 5.0 and J2SE 1.4?